The effects of superconductor-stabilizer interfacial resistance on quench of a pancake coil made out of coated conductor

We present the results of numerical analysis of normal zone propagation in a stack of $YBa_2Cu_3O_{7-x}$ coated conductors which imitates a pancake coil. Our main purpose is to determine whether the quench protection quality of such coils can be substantially improved by increased contact resistance between the superconducting film and the stabilizer. We show that with increased contact resistance the speed of normal zone propagation increases, the detection of a normal zone inside the coil becomes possible earlier, when the peak temperature inside the normal zone is lower, and stability margins shrink. Thus, increasing contact resistance may become a viable option for improving the prospects of coated conductors for high $T_c$ magnets applications.Comment: 9 pages, 4 figure

Distribution, Hybridization, and Taxonomic Status of Two-lined Salamanders (\u3ci\u3eEurycea bislineata\u3c/i\u3e complex) in Virginia and West Virginia

We used three diagnostic protein markers to examine salamanders of the Eurycea bislineata complex at 80 localities in Virginia and West Virginia. Two groups were strongly differentiated and met at a narrow contact zone. Rare hybridization was observed as well as limited introgression up to 5 km north and 10 km south of the contact zone. At the contact zone, 1% F1, 2% F2, 32% backcross, and 66% parental genotypes were observed. This pattern of parapatric distribution with limited hybridization and introgression argues for the recognition of Eurycea bislineata and E. cirrigera as separate species

Secondary contact and admixture between independently invading populations of the Western corn rootworm, diabrotica virgifera virgifera in Europe

The western corn rootworm, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae), is one of the most destructive pests of corn in North America and is currently invading Europe. The two major invasive outbreaks of rootworm in Europe have occurred, in North-West Italy and in Central and South-Eastern Europe. These two outbreaks originated from independent introductions from North America. Secondary contact probably occurred in North Italy between these two outbreaks, in 2008. We used 13 microsatellite markers to conduct a population genetics study, to demonstrate that this geographic contact resulted in a zone of admixture in the Italian region of Veneto. We show that i) genetic variation is greater in the contact zone than in the parental outbreaks; ii) several signs of admixture were detected in some Venetian samples, in a Bayesian analysis of the population structure and in an approximate Bayesian computation analysis of historical scenarios and, finally, iii) allelic frequency clines were observed at microsatellite loci. The contact between the invasive outbreaks in North-West Italy and Central and South-Eastern Europe resulted in a zone of admixture, with particular characteristics. The evolutionary implications of the existence of a zone of admixture in Northern Italy and their possible impact on the invasion success of the western corn rootworm are discussed

Translanguaging in the contact zone: Language use in superdiverse urban areas

People and languages have always been on the move, and diversity in the world’s urban areas has been well-documented since antiquity. By the same token diverse languages and cultures have always been in contact. However, the mass movement of people associated with globalisation, coupled with the mobility of the linguistic and semiotic message in online communication, now indicate social and linguistic diversity of a type and scale not previously experienced. With the emergence of new sociolinguistic configurations that such mobility entails, so new theoretical understandings are developed and deployed. In this paper I discuss two concepts that are current in contemporary sociolinguistics – superdiversity and translanguaging – and explore their relevance for research into contemporary language use.

Modeling of temperature distribution in orthogonal cutting with dual-zone contact at rake face

In this study, an analytical model is developed in order to calculate the temperature distribution in orthogonal cutting with dual-zone contact at the rake face. The study focuses on heat generation at the primary shear zone and at the rake face. The material behavior at the primary shear zone is represented by Johnson-Cook constitutive equation whereas the contact at the rake face is modeled by sticking and sliding friction zones. This new temperature distribution model allows obtaining the maximum temperature at the rake face and helps determining two dimensional temperature distribution in the chip. The simulation results obtained from the developed model are also compared with experimental results where good agreement is observed

The effects of superconductor-stabilizer interfacial resistance on quench of current-carrying coated conductor

We present the results of numerical analysis of a model of normal zone propagation in coated conductors. The main emphasis is on the effects of increased contact resistance between the superconducting film and the stabilizer on the speed of normal zone propagation, the maximum temperature rise inside the normal zone, and the stability margins. We show that with increasing contact resistance the speed of normal zone propagation increases, the maximum temperature inside the normal zone decreases, and stability margins shrink. This may have an overall beneficial effect on quench protection quality of coated conductors. We also briefly discuss the propagation of solitons and development of the temperature modulation along the wire.Comment: To be published in Superconductor Science and Technology. This preprint contains one animated figure (Fig. 6(a)). when asked whether you want to play the content, click "Play". Acrobat Reader (Windows and Mac, but not Linux) will play embedded flash movies. In the printed copy Fig. 6(b) will show the temperature profile at gamma t=15

Dancing in the 'contact zone'

In October 2002 I performed and exhibited Troppo Obscura: A Peepshow of Historical Perversity at the Performance Space as part of the multicultural Arts festival, Carnivale, in Sydney, Australia. Troppo Obscura was a multimedia installation that explored some aspects of the complex relationships between the West and Asia. The work looked at a large range of possibilities, from the colonial gaze through to personal relationships forged through artistic endeavour. This paper focuses on one such personal relationship addressed in the installation, namely that between traditional master mask dancer Ibu Sawitri from Cirebon on the West coast of Java, Indonesia, and myself, a Sydney based contemporary dancer and performance artist. Between 1992 and 1999, the year Ibu Sawitri passed away, I spent many long-term visits learning dance and living in Ibu Sawitri s house in Losari

Mechanisms of pattern formation during T cell adhesion

T cells form intriguing patterns during adhesion to antigen-presenting cells. The patterns at the cell-cell contact zone are composed of two types of domains, which either contain short TCR/MHCp receptor-ligand complexes or the longer LFA-1/ICAM-1 complexes. The final pattern consists of a central TCR/MHCp domain surrounded by a ring-shaped LFA-1/ICAM-1 domain, while the characteristic pattern formed at intermediate times is inverted with TCR/MHCp complexes at the periphery of the contact zone and LFA-1/ICAM-1 complexes in the center. In this article, we present a statistical-mechanical model of cell adhesion and propose a novel mechanism for the T cell pattern formation. Our mechanism for the formation of the intermediate inverted pattern is based (i) on the initial nucleation of numerous TCR/MHCp microdomains, and (ii) on the diffusion of free receptors and ligands into the contact zone. Due to this inward diffusion, TCR/MHCp microdomains at the rim of the contact zone grow faster and form an intermediate peripheral ring for sufficiently large TCR/MHCp concentrations. In agreement with experiments, we find that the formation of the final pattern with a central TCR/MHCp domain requires active cytoskeletal transport processes. Without active transport, the intermediate inverted pattern seems to be metastable in our model, which might explain patterns observed during natural killer (NK) cell adhesion. At smaller TCR/MHCp complex concentrations, we observe a different regime of pattern formation with intermediate multifocal TCR/MHCp patterns which resemble experimental patterns found during thymozyte adhesion.Comment: 12 pages, 8 figure

The Neumann sieve problem and dimensional reduction: a multiscale approach

We perform a multiscale analysis for the elastic energy of a $n$-dimensional bilayer thin film of thickness $2\delta$ whose layers are connected through an $\epsilon$-periodically distributed contact zone. Describing the contact zone as a union of $(n-1)$-dimensional balls of radius $r\ll \epsilon$ (the holes of the sieve) and assuming that $\delta \ll \epsilon$, we show that the asymptotic memory of the sieve (as $\epsilon \to 0$) is witnessed by the presence of an extra interfacial energy term. Moreover we find three different limit behaviors (or regimes) depending on the mutual vanishing rate of $\delta$ and $r$. We also give an explicit nonlinear capacitary-type formula for the interfacial energy density in each regime.Comment: 43 pages, 4 figure